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Discussion in 'Amps and Cabs [BG]' started by René_Julien, Jul 18, 2012.
Would this in theory reduce combing effect and improve dispersion a bit?
Not with the 4 speakers still mounted in a square pattern.
So the entire surface of the speakers may not overlap horizontally? (Not just the centerpoints?)
So diagonal patterns like Bergantino 412 or Aguilar 412 are as bad as a square pattern, or a little better because the centerpoints of the speakers are closer togheter on the horizontal axis?
No, just change the pattern of the filtering.
But wouldn't it theoretical be better across the horizontal and vertical plane? By shifting the combing to 30° and 60° angled planes?
I realize in practical sense this probably does make not much difference that placing the cab normally.
BFM has said that diagonal is better than horizontal, but not as good as vertical.
Perhaps you should check out his forum for a solid answer.
Where dispersion is concerned, view the whole cab as one sound source, in this case, about 20-22" wide. That will start to beam lower in frequency than even an 18 would. So, the narrower/closer to vertical you get, the higher it can play before losing too much response off to the side and being left with a hotspot on center with the cab. Staggered drivers would be better than horizontally placed, vertical better still.
As far as comb filtering goes, it will always be present whenever there is more than a single source playing the same bandwidth. In this case, the 4 drivers in the cab are 4 individual sources. The closer they are positioned, the higher in frequency the combing will come into play bit it will still always be there.
What you do by mounting the drivers vertically is eliminate the comb filtering from the horizontal plane and move it to the vertical plane. This works because in general, our ears don't change position vertically much. Even if you're jumping up and down, unless you're right next to the cab, you won't hear much difference in sound....but...somebody walking across the stage or audience could hear something different every step of the way. Moving the destructive interference to the vertical plane makes it hard to even notice and gives a more quality sound to a wider swath of the audience. Comb filtering and dispersion kinda go hand in hand that way.
Translate that to a typical PA setup with mains left and right, and yes, there will be comb filtering and phasing stuff all over...but...your ear sort of "latches onto" whichever is dominate in volume or whichever sound arrives first, so it's not as bad as it may seem. If you're in the middle, you get fairly even representation from both sides. If you're off to one side, the sound from the main on your side will arrive at your ear both first, and louder, and that helps to mask the interference from the other side.
Also with comb filtering, there is a point where if the "teeth" are close enough together, our brain can't decipher the difference anymore and "hears it" as one sound. Standard smoothing for speaker measurements, etc. is 1/6 octave because out brain can't resolve to less than that. If you've ever looked at a measured response chart for a speaker that wasn't smoothed to 1/6 octave, the whole thing looks like saw teeth, no matter how good a speaker it is.
Good links, etc. in the sticky up there, and tons of good info at Bill's forum.
Set it on the floor normally and then put a two foot wide vertical divider to separate the two vertical pairs of speakers.
But PLEASE, BILL, COME BACK!!!!!!!
So in essence tilting the quad cab sidways would be better than flat on the ground?
I understand that vertical is ideal. But the reason why I asked this question is: what if you have a 4x10 you really like... could you position it better?
Thanks. I admit that I don't full grasp comb filtering and beaming.
What I don't have a clear view on is wave lenghts in general. I spent a lot of time searching this forum yesterday and found good input on the subject by BFM, Alex Claber, agedhorse an greenboy. I take these guys word for truth, but I still have trouble reading the science behind it.
That's why this simple theoretical question I asked. It brings out more questions for me to research on.
The best 410 would be a vertical array. But nobody makes one because it's a little impractical to transport, and you can just as easily stack 2 210's.
Okay, so I'm off to make a 30° wedge then.
It would look interesting.
However it's rather a case of attempting to make a silk purse out of a sow's ear!
I realize that. But improvement is improvement I guess.
Sunday I have a chance to play in a bigger room. I'll try to test it out if I notice any difference across the room by tilting this way.
This was just something going through my mind. Ideally my choice of rig would be a 1x15 or 2 1x15's stacked.
Now there you've got something.
I think any sonic improvement made by playing your cabinet diagonal would be more academic than practical...plus you lose your floor coupling.
I already got a great 1x15 cab. But I'm not getting rid of my beloved 4x10.
Both are very great and very different cabs, and each on their own are way too loud for what I need. (Probably a low power 1x12 combo would suit my gigging needs.)
With the cab tilted up on edge like that, you might be somewhat taking it out of a typical 1/2 or 1/4 space setup to something in between with some bass/lowmids being able to wrap around the bottom of the cab.
Although, that may follow the same concept as elevating cabs, where up to a couple feet works as far as bass out in the room, just sounds less bassy to the player because they can hear the mid content better.
Again, maybe more academic than practical, but could be remedied by cutting a solid face wedge to put at the front edge of the cab, thereby extending the baffle down to the floor like it is in the regular setup.
Having 4 speakers in a square pretty well limits your positioning options. If it was something like a 212 with the speakers mounted in opposite corners, the tilt/wedge/baffle extender likely make a greater improvement.
Thanks for the insight, when I try this I'll keep this in mind.
But I shouldn't expect miracles.
Certainly won't hurt to try any of this stuff. Kudos to you for thinking into it, experimenting with it and not listening with your eyes.
Some difference may be more apparent up close, like having a driver a little higher up/closer to the ear or taking some woof/rumble off the stage. Some may be more apparent further out or off to the side or not at all, but cool stuff nonetheless.